Induction coil



P 1960 H. J; THIELSCH 2,933,584

INDUCTION COIL Filed July 5, 1958 2 Sheets-Sheet 1 INVENTOR.

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April 19, 1960 INDUCTION COIL FIG?) 4 \4.- 1 r v any %a 7 BY FIG. 5 EM; c

ATTORN Y H. J. THIELSCH 2,933,584

Un St w P e INDUCTION COIL Helrnut J. Thielsch, Cranston, R.I., assignor to Grinnell Corporation, Providence, R.I., a corporation of Delaware Application July s, 1958, Serial No. 746,418

7 Claims. or. 219-1059) This invention relates to an induction heating coil which exhibits particularly utility in the heating of metal pipes during construction. It has long been the practice in various metal arts to employ induced electrical eddy currents to heat metal, and this method of heating has found great acceptance in the welding art where pipe ends must be heated preparatory to welding and where heat must be applied to relieve stresses in a completed weld or otherwise heat treating.

In field construction the induction coils are located on the pipes when the latter are in their installed positions, and accordingly it has often been the practice to manually wind the coils around the pipes. In the case of large diameter pipes this wrapping procedure requires great labor particularly where the piping is in restricted locations. While the art is aware of certain efforts to advance the procedure beyond this crude stage, no simple, inexpensive and relatively foolproof apparatus has been available which can readily be applied to and removed from the pipe in the installed position of the pipe and which can carry large electrical currents for sustained periods.

The invention here disclosed resides in a multi-turn coil which carries a coolant fluid and which can be opened to receive a pipe. The convolutions are partially formed of a bendable conduit which allows the coil to spread open, and the turns are in spaced and parallel relationship with their ends brought together and forced apart by a single quick-acting latch device.

In the drawings:

Fig. 1 is a perspective showing the induction heating coil of this invention,

Fig. 2 is a plan view of the coil of Fig. 1 with certain elements partially broken away,

Fig. 3 is a cross-sectional view of a' portion of the coil shown in Fig. 1,

Fig. 4 is a view taken along line 4-4 of Fig. 3, and

Fig. 5 is a perspective, partially broken away, of a portion of the coil shown in Fig. 1.

In Fig. 1 the numeral denotes a latching and contact mechanism for securing the ends of the induction coil together. The numeral 12 denotes one of the halves of the contact mechanism and the numeral 14 denotes the other half. Reference now to Figs. 2, 3 and 4 will give a more precise understanding of these elements. Except for its end blocks 15 which serve as guides, the right half 12 is composed of a plurality of conductor blocks 16 having male contact elements 18. The blocks 16 are held together by a plurality of insulated elongated bolts 24 and are electrically insulated from one another by sheets 28 of insulating material. Insulating ferrules 30 are also placed between the blocks and, together with integral block cavities 31, form a single elongated manifold chamber 32 which communicates with all of the blocks. An inlet port 34 communicates with the manifold chamber 32 at one end of the section 12.

The left hand portion 14 of the latching mechanism includes a pair of aligning end blocks 19 and a plurality of conductor blocks 20 with sockets 22 receiving connector blades 18. Portion 14 also includes spacing members 28 which insulate the blocks 20 from one another and ferrules 30 which together with integral cavities 31 in the blocks define a single manifold chamber 33 com municating with each of the blocks. An outlet port 36 at one end of portion 14 communicates with this manifold chamber.

The numerals 38 denote the convolutions of the coil and are formed of stiff, hollow copper tubes. Each such convolution has one of its ends secured to a block 16 and the other end secured to a block 20. The connection is to alternate blocks. Note that the lower right block 14 (Fig. 2) and the upper left block 14 each receive a convolution end. In addition each convolution has an asbestos sleeve 39 for'heat and electrical insulating purposes. The convolutions 38 together with the chambers 32 and 33 form a plurality of parallel, curved fluid paths from the inlet port 34 to the outlet port 36.

Each convolution 38 is provided at substantially its middle portion (see Fig. 5) with a short length 40 of flexible, hollow conductor cable. This cable is removably attached to threaded ferrules 41 and may be replaced if desired. Four clamps 52 hold the inflexible portions of the convolutions 38 in parallel relation.

The toggle latch mechanism employed for opening and closing the coil will best be understood by reference to Figs. 2 and 3 of the drawings wherein the numerals 42 denote a pair of upstanding lugs secured to the section 14. Each lug is provided with a notch 43 which receives the free end of one closed link 44. The links 44 are each pivotally secured at 45 in a rotatable handle plate 46, and are maintained in parallel relationship by a clamp 47. Each handle plate 46 is rotatably secured to 1 the portion 12 on one of a pair of upstanding lugs 48,

and the handle plates are joined by a handle bar 49- whereby both handle plates can be operated at the same time. For ease in carrying the coil, an upstanding handle 50 may be secured to one of the portions of the latch, for example to the portion 14.

The coil is employed in the following manner. Assuming it to be initially in its open position, it is first placed around the ends of two abutting pipe sections which are to be pro-heated for welding or which are to be heat-treated for stress relief after welding. The two portions of the latch mechanism at the coil ends are brought up and around the pipes and the prongs 18 introduced slightly into slots 22. Because of the tight fit in the final closed position between these prongs and slots the mechanical advantage of the latch mechanism is required to effect this final engagement. The operator swings the links 44 so that their free ends fall intonotches 43 in the blocks 42. The handle bar 49 is now turned clockwise (see Fig. 3) until it is in the position shown. At this point the links 44 are each in an over center" position and the handle will not move back in a counterclockwise direction until it is so moved by an operator. Inlet port 34 is connected to a source of coolant fluid, usually water, and outlet port 36 is secured to a suitable drainage. The coolant now fills the manifold chamber 32 in element 12, thence passes through the convolutions 38 around to the manifold chamber 33 in element 14 and thence outward through the outlet port 36. At the same time a heavy electric current is passed through the coil, the electric terminals preferably being coincident with the inlet and outlet ports 34 and 36.

The current path through the induction coil is continuous and in the form of a helix. The path, assuming the current to also flow in through port 34 and out through port 36, is to the first end block 15 and convolution 38 of the unit 12 (see Fig. 1), then around the Patented Apr. 19, 1960 3' pipe to the first block 20 of unit 14'. From this block it passes to and through prongs 18 to the first block 16 of unit 12 and thence through the second convolution 38 around to the second block 20, thence to the second block 16, and finally exits through upper block 19 and outlet port 36 (see Fig. 2)..

After the heating has been completed the current and coolant fluid. are shut off and. the coil. is ready to. be removed. The handle bar 49 is moved (see Figs. 1 and 3) counterclockwise which causes links 44 to positively push apart and separate the sections 12 and 14. When the prongs 18 have been withdrawn nearly all the way from. the sockets. 22 the free. ends of the links are disengaged from the slots 43 in lugs 42 and the coil may be again. spread to its open position by the bending of the flexible portions 4.0 of each. or. the convolutions.

I claim:

1.. An induction coil comprising aset of male conductor terminals electrically insulated from each. other and a set of' female conductor terminals electrically insulated from each other, each set having. an interior manifold fluid chamber, a plurality of at least partially flexible hollow conductors, each of which electrically connects a male conductor terminal. to a female conductor terminal and each of which communicates with the said manifold chambers, a fluid. inlet port at one or. the

chambers and av fluid outlet port at. the other of the chambers, the current path defined by the conductors and terminals between the inlet and outlet ports being. in the form of a helix.

2. An induction coil comprising a plurality of segments which. are hollow for carrying fluid and which conduct electricity, each segment being, at least partially flexible and electrically insulated with respect to the other segments, one end of each segment being. secured to one of a first set of terminals which are electrically insulated from each other and the other end of each segment being secured to one of a second setof. terminalswhich are electrically insulated from each other, means for releas-- ably electrically connecting. the two sets of terminals to form a single, helical current path through the terminals and segments, and a fluid manifold chamber formed in each set of terminals and communicating with the interiors of. the segments.

3. An. induction coil. comprisingv a: set? of. aligned and insulated rnale conductor terminals and. a. set of aligned and. insulated. female conductor terminals, means for releasably electrically connecting the two sets, a". plurality of at. least. partially flexible hollow insulated conductors each joining a male and female-terminal to form a current path, a first fluid port at one end of the set. of. female terminals and a second fluidv port at one end of the set of male terminals, a chamber formed within. each set. communicating with the interiors. of the hollow conductor and with the port of that set, the current path through the insulated conductors and across the insulatedterminals being. a continuous helix.

4. An induction coil comprising a set of insulated male conductor terminals and a set of insulated female conductor terminals, each set having an interior fluid manifold chamber, a port in each chamber, means for releasably electrically connecting together the terminals of the sets, said means including a rotatable link having one end pivotally mounted on one set and having its other end releasably engageable with the other set, the pivoted end swingable through an are away from and toward the other set to force the sets into and out of engagement, a plurality of hollow and at least partially flexible conductors each joining a terminal of one set to a terminal of another set to form a continuous helical current path, the hollow conductor ends communicating with the manifold chambers and forming fluid paths between said chambers.

5. An induction coil comprising a first set of conductor terminals electrically insulated from each other connected to a. second set of conductor terminals also electrically insulated from each other, the terminals having cavities therein, a plurality of at least partially flexible hollow conductors joining the cavities in the first and second terminal sets to form a continuous hydraulic path, the terminals and conductors defining a current path in the form. of a helix, the continuity of the hydraulic path being independent of the electrical connection between the terminals of the two sets.

6. An induction coil comprising a first set of conductor terminals electrically insulated from each other connected to a second set of conductor terminals also electrically insulated from each other, the terminals having cavities therein, a plurality of at least partially flexible hollow conductors joining the cavities in the first and second terminal sets to form a continuous hydraulic path, the terminals and conductors defining a current path in the form of a helix, the hydraulic path at the ends of each hollow conductor having a direction parallel to a plane defined by the connections between the terminals of the two sets.

7'. An induction coil comprising a first set of conductor terminals electrically insulated from each other connected to a second set of conductor terminals also electrically insulated from each other, the terminals having cavities therein, a plurality of at least partially flexible hollow conductors joining. the cavities in the first and second terminal sets to form a. continuous hydraulic path, the terminals and conductors defining a current path in the form. of. a helix, the hydraulic path at the ends of each hollow conductor having a direction parallel to the axis of the: helix.

References Qited in. the file of this patent UNITED STATES PATENTS 2,180,513 Fugill et a1 Nov. 21, 1939 2,343,889 Denneen et a1 Mar. 14, 1944 2,649,529 Smith et a1. Aug. 18, 1953 2,783,351 Conkling. et a1 Feb. 26, 1957 

